T. Rex's Missing 3rd Finger Found
Oct. 17, 2007 — It's bad enough to misplace a finger, much less have it lost for 65 million years. But after decades of searching, paleontologists at Montana's Hell Creek have found the missing third finger of one of Tyrannosaurus rex's undersized "hands."
The finger suggests that T. rex had a powerful wrist and its hands were probably able to hold onto chunks of flesh while the monster's gnarly jaws did all the killing.
The newfound bone is a right metacarpal, equivalent to one of the long bones in the palm of a human hand, explains T. rex investigator Elizibeth Quinlan of Fort Peck Paleontology, Inc., in Fort Peck, Montana. She plans to present the discovery on Oct. 28 at the annual meeting of the Geological Society of America in Denver.
"It's unquestionably the metacarpal," Quinlan told Discovery News. No previous T. rex remains have ever been found with a third metacarpal, despite the fact that the other bones suggested its presence. "There is a notch in the side of the second metacarpal that was just begging to have something fit into it."
The revised anatomy of the hand suggests there was a very strong tendon that attached to second metacarpal, giving the hand a pretty decent grip, she said. Still, the puny limbs were almost certainly not used by T. rex to grapple with prey or kill.
"We were thinking that T. rex did use its upper appendages not so much in hunting but in feeding," said Quinlan. That means ripping off pieces of flesh from corpses and clutching the stuff to keep it from other hungry predators. "We don't think their table manners were very good."
"I would strongly support (the hand) being used for carrying a piece of meat away," said paleontologist Scott Hartman, science director of the Wyoming Dinosaur Center in Thermopolis. "There is a reason that carrying meat away would be useful."
One reason is that the T. rex head is already so large and heavy that adding the weight of a large slab of meat between its teeth would make it unable to tip back and stand up, Hartman said. Holding meat with the arms, which are lower, avoids that overloaded teeter-totter effect.
Another possibility is that the hands were parenting tools. They would have made it possible for a T. rex to carry yummy slabs of dino flesh to its carnivorous babies, Hartman said.
That said, the new finger bone is not going to cause much change to reconstructions of T. rex, says Hartman. Throughout the evolution of meat-eating dinosaurs there was a trend towards fewer fingers, with the earliest having five fingers and the T. rex having two. This newfound nubbin of a third finger was already on its way out, and did not stick out much, he said.
"In another 10 million years they would have lost (the third finger) completely," said Hartman. Unfortunately for them, however, the age of dinosaurs ended before that could happen.
New Tyrannosaur Had More Teeth Than T. Rex
The newly found toothy tyrannosaur featured a hole in its skull and was recovered from New Mexico. The skull of a new genus and species of a deep-snouted, Late Cretaceous tyrannosaur found recently in New Mexico.
A new tyrannosaur was found in a New Mexico federal wilderness area. The dinosaur is the first new genus and species of tyrannosaur to be named from western North America in over 30 years. The dino had more teeth than its famous cousin, Tyrannosaurus rex.
A newly found 29-foot-long tyrannosaur flashed more teeth than the well-known Tyrannosaurus rex, with which it shared a common ancestor, according to a paper in the latest Journal of Vertebrate Paleontology.
Remains of the badlands dinosaur, Bistahieversor sealeyi, were collected in the first paleontological excavation from a federal wilderness area, the Bisti/De-na-zin Wilderness of New Mexico. The dino's remains were removed VIP-style, airlifted by a helicopter operated by the Air Wing of the New Mexico Army National Guard.
"Bistahieversor sealeyi is the first valid new genus and species of tyrannosaur to be named from western North America in over 30 years," said co-author Thomas Williamson, curator of paleontology at the New Mexico Museum of Natural History.
It lived 74-75 million years ago, close to 10 million years before T. rex emerged. The earliest known tyrannosaurs date to about 167 million years ago and came from the American West, according to Carr. It is now therefore believed that the rough and tumble Tyrannosauridae family was born in the U.S.A.
Several features distinguish the new dinosaur, according to Williamson's partner on the project, Thomas Carr, who is director of the Carthage Institute of Paleontology and an assistant professor of biology at Carthage College.
It had around 64 teeth, while adult T. rex, had just 54.
Before the Tyrannosaurus, Guanlong Roamed China
Chinese and American scientists have discovered what appears to have been the granddaddy of all tyrannosaurs, a primitive crested dinosaur that lived 160 million years ago in northwestern China.
The scientists announced yesterday that an analysis of two fossil specimens suggested that they were either remains of the most primitive tyrannosaur known or the first branch on the family tree leading to Tyrannosaurus rex, the symbol of tooth and claw predation in the age of reptiles.
James M. Clark, a paleontologist at George Washington University, said the discovery "shows us how ancestors of tyrannosaurus took the first step that led to the giant T. rex almost 100 million years later."
The research team, led by Dr. Clark and Xing Xu of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, named the new species Guanlong wucaii. The first, or generic, name is derived from the Mandarin word for "crowned dragon," a reference to its large, fragile crest. The second, or species, name refers to the rich colors of the Junggar Basin, the remote discovery site north of the Tian Shan range.
The discovery, made in 2002, is described in detail in today's issue of the journal Nature. Dr. Clark and other team members discussed the ancestral tyrannosaur yesterday at a news conference in Washington.
Two specimens of the new species were uncovered near one another. The most revealing one, the scientists said, was a nine-foot-long, 12year-old adult with the crested head believed to be typical of the species. The other was a smaller, 7-year-old juvenile. Almost immediately, Dr. Clark said, "we knew we had something fairly rare."
The clearest evidence of an ancestral link to tyrannosaurs were the teeth and pelvic structure of the two skeletons. Closer examination, Dr. Clark said, dispelled any lingering skepticism and showed a definite relationship with later tyrannosaurs.
Mark A. Norell, a paleontologist at the American Museum of Natural History in New York and a team member, said, "The discovery of this basal tyrannosaur is giving us a much broader picture of the diversity of this group and its ancestors."
Dr. Norell noted several primitive traces in the skeletons, including the presence of long forearms and three-fingered hands. The well-known T. rex, which lived about 70 million years ago, toward the end of the Cretaceous period of geologic time, evolved short forearms that were virtually nonfunctional two-fingered hands, and a mammoth body two or three times the length of these early ancestors.
The differences suggest that the newfound animals were an intermediate step in evolution between primitive coelurosaurs, a group of birdlike dinosaurs, and tyrannosaurs.
The skeletons were found in sediments from the late Jurassic period, when the site in the desert basin was a warm land of lakes and marshes. The region of the discovery, near China's borders with Mongolia and Kazakhstan, was previously explored by a Chinese-Canadian fossil hunting expedition in the 1980's. Other paleontologists said they were not surprised that the region had yielded more discoveries from earlier epochs in the time of dinosaurs.
Only a few scraps of dinosaur fossils were previously uncovered in the Jurassic deposits, but Dr. Clark said the age of the Guanlong specimen was "about where we would expect the oldest tyrannosaurs to be."
The earliest previously known tyrannosaur was a 130-million-year-old feathered specimen, Dilong paradoxus, which American and Chinese scientists reported two years ago. No signs of feathers were found on the two Guanlong specimens.
The presence of a crest on the Guanlong adult's head was a complete surprise, Dr. Clark said, showing that there was "clearly still much more to be learned about early tyrannosaurs."
The research team said the crest was about as thin as a tortilla and only two and a half inches high. It appeared to be filled with air sacs and reminded the paleontologist of the ornamental features found on some living birds, like cassowaries and hornbills.
Dr. Norell said the crest was too thin to have provided much protection, or to have been used in butting heads in combat. More likely, he said, the crest of these "crowned dragons" had something to do with attracting mates or identifying fellow species members.
Tiny Tyrannosaur: T. Rex Body Plan Debuted In Raptorex, But 100th The Size
A 9-foot dinosaur from northeastern China had evolved all the hallmark anatomical features of Tyrannosaurus rex at least 125 million years ago.
University of Chicago paleontologist Paul Sereno and five co-authors describe the newly discovered dinosaur in the Sept. 17 Science Express, advanced online edition of the journal Science.
Raptorex shows that tyrannosaur design evolved at "punk size," said Sereno, a National Geographic Explorer-in-Residence, "basically our bodyweight. And that's pretty staggering, because there's no other example that I can think of where an animal has been so finely designed at about 100th the size that it would eventually become."
Raptorex displays all the hallmarks of its famous descendant, Tyrannosaurus rex, including a large head compared to its torso, tiny arms and lanky feet well-suited for running. The Raptorex brain cast also displayed enlarged olfactory bulbs—as in T. rex—indicating a highly developed sense of smell.
"It's really stolen from tyrannosaurids all the fire of the group," Sereno said. All that Raptorex left for its descendants is "a suite of detailed features largely related to getting bigger."
Sereno marvels at the scalability of the tyrannosaur body type, which when sized up 90 million years ago completely dominated the predatory eco-niche in both Asia and North America until the great extinction 65 million years ago at the end of the Cretaceous Period.
"On other continents like Africa, you have as many as three large predators living in the same areas that split among them the job of eating meat," he said. But in Africa, the allosaurs never went extinct, as they did in North America, possibly presenting an evolutionary opportunity for Raptorex. "We have no evidence that it was a competitive takeover," said Sereno, "because we have never found large tyrannosaurs and allosaurs together."
Henry Kriegstein, a private fossil collector, brought the nearly complete Raptorex skeleton to Sereno's attention after buying it from a vendor. After Sereno and colleagues finish amore detailed study of Raptorex, it will be returned to a museum in Inner Mongolia, the place where the fossil was illicitly excavated.
Funding was provided by The Whitten-Newman Foundation and the National Geographic Society.
Raptorex will appear in the world premiere special BIZARRE DINOS, on the National Geographic Channel at 8 p.m. ET/PT Sunday, October 11.